NASA and NOAA satellites show that the Antarctic ozone thinning covers the largest expanse of territory since the depletion developed in the early 1980s. The measurements were obtained this year between mid-August and early October using the Total Ozone Mapping Spectrometer (TOMS) instrument aboard NASA's Earth Probe (TOMS -EP) satellite and the Solar Backscatter Ultraviolet Instrument (SBUV) aboard the NOAA-14 satellite. "This is the largest Antarctic ozone hole we have ever observed, and it's nearly the deepest," said Dr. Richard McPeters,Principal Investigator for Eareth Probe TOMS.